A833OD inspection results... thoughts?
I need to subscribe to that thread when you start it. I have an A833 O/D aluminum cased 4 speed. Not sure which steel bushing you are talking about needing to help prevent self destruction. I planned on going through mine. I never rebuilt one before, however i'm not a stranger to manuals. I rebuilt a muncie M21, and a new process A555 high capacity fwd transaxle. My A833 doesnt have any burred or battered teeth, but i was going to freshen it up with new seals, gaskets, synchro brass rings, and and bearings anyways. I was going to put this behind a 408. I figured my 67 barracuda is light enough that it could handle it. I really wanted it to wind it out for the 1-2 shift, and just use 4th or O/D gear for highway driving with 3.73s. I guess by previous posts the O/D gear sitting in the 3rd gear slot is kinda delicate for V8 use. No bang shifting into overdrive unless i want it to go "boom".
Ideally id like a Passon A855 O/D box, anybody got $4,500 to lend me lol. Maybe if i win the lottery.
Mat
That 408 will put out more torque obviously, than my 367. But it's not the torque per se, that wallers out that front hole. It's also related to the load that's attached to the driveshaft. With 3.73s the power will pass thru the box with a lot less loading on the gears. I run 3.55s, and 295s on the street most of the time. And I saw on the gas pedal pretty good,or used to in my younger years,lol.
But I gotta say that there will be no winding your combo out on the 1-2. The low gear ratio is 3.09 and coupled with the 3.73s, and 28s, she'll be hitting 6000 at 44 mph. With a 408, this will be a little over 2 seconds out, and she'll be spinning all the way.
Now second,that one you can wind out, as 6000 won't come up until 80mph and that will be around 7 or 8 seconds out,and in all likely hood still spinning.
Your cruizer will make 65=2124ish, So depending on your cam, this could be good or bad, as regards fuel-mileage..
What I'm trying to say is this; that box may not be suited to your combo, Low is too low and hi is too hi, and the splits are more suited to a low rpm engine.
Your 408 certainly won't need a 3.09 x 3.73 =11.53 starter gear. This is enough gear that even a 273 can light up the tires. Ima thinking you could get away with about 8.6 as a starter, which would be a regular old 2.66 low with 3.23s to get 8.59. Slipping out the clutch at 160 ftlbs, this makes 1374 ftlbs into the rear axles and more than enough to break the biggest tires loose that you can put into the stock tubs. And my guess is that your 408 can make more than that 160ftlbs by 1800rpm.
The flipside of 3.23s is that they will cruise at 65=2519 with those 28s, and I'm betting the cam in that 408 will like that better than 2124, and so the fuel-mileage may not change much. And you won't need to downshift to pass. (you will with the od box or risk splitting that od gear.
And finally with 3.23s you can "wind that first gear out" to 6000=58 mph, and you can do the 1/8 at the top of third trapping very near the power-peak, and the quarter in the middle of 4th, at or near the torque peak..
And the best part for me is 35mph is 2550 in second,very sneaky, but downshifting into first, the engine will hit 3600 and the car will explode with acceleration. I wonder if the 408 couldn't do that even in second,lol,no downshift required. And if it handles that,you're good to wind it out to over 80mph in second.
The only downside to this combo is if you can't tune your engine to hit 160 ftlbs smoothly at an rpm that you're comfortable with., and that it doesn't explode with power right after that,lol.
You know, not like an old Mustang that you have to rev it to 3000 just to get moving. I never liked that. 302s were just too small for me.
So again it comes down to your cam and compression marriage, and how well the carb will work at that small throttle opening.
In my entire life, l've never had any engine bigger than my 367, ever. It handled this situation very well with a
[email protected], and even a 750 DP, allbeit with a 8 or 9% more starter gear. It was a dump it and go deal. That is to say, blip the throttle and more or less dump the clutch, letting the heavy street flywheel do the job.I currently run a
[email protected] and a starter gear of 10.97,so 26% more than the above described 3.23s and 2.66. This is also a dump it and go deal. It's way more gear than I need, to spin 295s. I only run it cuz I have the GVOD for cruising 65=2244, and I'm too lazy to put the 3.23s back in, or even 2.94s My combo likes 2244 to cruise with so I just suffer not being able to wind it out.....Well that's not exactly true; when I run outta revs in first I hit the splitter button, and she's good to 68ish mph..........if the tires stop spinning.........lol
I'm reasonably confident that you can get a tune like this into your 408 with any reasonable street cam and compression marriage.
And the clincher is/are that I've never heard of anybody breaking an A833 on the street, so your worries are over,and up here, $250 is the going price, the last time I looked. Swap-meet od boxes were $50 back in 2004.
And finally my box has the 3.09 low. he ratios are 3.09-1.92-1.39-1.00 as compared to the standard box having; 2.66-1.91-1.40-1.00.
So you can either keep the 3.23s for 16% more blast of power. Or back up to say 2.94 rear gear, and still have a starter of 9.08,(which is 5.7% better than the 3.23x 2.66) but now 65 will be 2293,( which is 226rpm lower or about 8.9% less). With the 9.08 starter gear you can still wind it out to 60=6540rpm,or about 5 seconds, then ease it into overdrive. You will of course likely be spinning the whole way,lol. On second thought, slam it into direct first.
